This invention relates to a telephone line testing device for use with a PABX.
U.S. Pat. No. 3,898,396 provides test equipment for verifying trunk routing in a telephone system. A series of spoken words is provided to identify the area code and the telephone exchange to which a trunk under test is connected. The equipment includes a plurality of input channels each coupled to a verification line for a corresponding telephone exchange. A ringing signal on any channel is detected and special logic circuitry is provided to identify the required telephone exchange digits and to produce a read out of the area code and exchange digits for that channel.
With PABX""s there is always a difficulty in identifying if a problem is the responsibility of the organisation that supplied and services the PABX and its associated wiring, or of the utility supplying the telephone lines. The present invention provides a solution thereto.
According to the invention there is provided a telephone line testing device for use with a PABX having a plurality of input lines connected to a plurality of telephone lines of a telephone system, each of the PABX input lines being associated with a telephone line, which includes
test circuitry having
a test signal generator for generating a test signal;
a ringing detector for detecting the presence of a ringing signal on a telephone line; and
a second switch means which is responsive to the ringing signal detector for automatically supplying a test signal generated by the test signal generator when a ringing signal is detected;
a first connecting means for connection to the telephone lines of the telephone system;
characterised therein that it further includes
a second connecting means for connection to the input lines of the PABX;
a first switch means for connecting a selected one of the telephone lines either to the PABX input line associated with that telephone line or the test circuitry.
It will be appreciated by those skilled in the art that the test signal generator may be connected directly to the first switch means and may then be energised by the second switch means when a ringing signal is detected, or it may be connected to the first switch means via the second switch means. It the test signal generator is connected directly to the first switch means it may have a sufficiently high impedance so that the telephone line is not closed when the first switch means is operated.
The first connecting means may include a plurality of first terminals to which a corresponding number of telephone lines may be connected.
The second connecting means may also include a plurality of second terminals to which a corresponding number of PABX input lines may be connected, there being the same number of second terminals as there are first terminals, and with designed first and second terminals being associated with one another.
The first switch means may include a plurality of mechanically operable switches, each switch having a first contact connected to an associated first terminal, a second contact connected to the second terminal associated with said first terminal, a third contact connected to the test circuitry, and a contactor for connecting the first contact to either the second or third contact.
The ringing signal detector may be connected to all the third contacts of the first switch means.
The test signal generator may be connected to all the third contacts of the first switch means via the second switch means.
The telephone line to be tested may be accessed via the PABX, using another telephone line.
By means of the invention a PABX telephone operator may, if there is a fault on one of the lines, determine easily and quickly if the fault is in the telephone line or in the PABX.
The invention is now described, by way of an example, with reference to the accompanying drawings, in which:
The telephone testing device may have a lighting protection means.
The telephone line to be tested may be accessed via the PABX, using another telephone line.
By means of the invention a PABX telephone operator may, if he believes that one of the telephone lines is faulty, easily and quickly identify which telephone line it is.